Day 14, 15 & 16 - Checking the status with the IVF lab at Mackay Memorial Hospital

We were given instructions to call the IVF lab on day 14. When we called, we were informed that 9 out of 9 eggs were fertilized and looks good at the moment. It is very likely that the transfer will be done on the 5th day after egg retrieval (ER) i.e. day 18. If there was any change, we will be informed via phone. However, the next day (day 15) we received a call from the lab to go to the hospital on day 16 to do a 3-day transfer. I became pretty worried that the embryos weren't developing as expected. We showed up at the IVF lab at 9:30 a.m on day 16. As it was a holiday, the lab was closed. We were given instructions to wait outside. We waited for about 5 minutes before an embryologist appeared and informed us that 4 out of the 9 eggs were doing well and the doctor had advised to let them culture for additional 2 days. I asked the embryologist if there is a risk that the embryos will stop developing if we let it grow for another 2 days. She said that is a possibility however given my age and the number of eggs, she doesn't think there should be any issue. I asked her the number of cells of the embryos and she mentioned 7's, 8 & 9. I was relieved to be sent back home as I prefer a single embryo transfer (SET) to a double embryo transfer (DET). I spent the rest of the day catching up on sleep as I wasn't really able to sleep the night before.